I'm not an expert, but it seems risky to trust MongoDB for that. Isn't it the wrong tool for that space?
MongoDB commits are asynchronous and fail silently by default. This is in opposition to ordinary SQL databases, which are synchronous and fail noisely by default.
You can enable that behavior for MongoDB, but then you're just getting ordinary SQL-style behavior, so why were you using MongoDB in the first place?
You mean "ACID transactions" and not SQL databases. Some NoSQL databases, such as HyperDex, provide ACID transactions.